Performance and durability studies of a catalyst-coated membrane containing a low-Ir-content Sr(Ti,Ir)O3 anode for use in proton exchange membrane water electrolysis

Proton exchange membrane water electrolysis (PEMWE) is expected to be used in the large-scale green hydrogen production. Reducing the Ir content of the anode catalyst is desirable, as the availability of Ir is limited, thus increasing the cost of PEMWE. To reduce the Ir content, a perovskite-type Sr(Ti,Ir)O3 is investigated. Characterization and activity studies in acid suggest that the composition realizing both high catalytic activity and low Ir concentration is SrTi0.67Ir0.33O3. Prototype catalyst-coated membranes (CCMs) containing SrTi0.67Ir0.33O3 anodes are prepared. Regardless of the small Ir loading of 0.17 mgIr cm−2, high efficiencies of 86.4 % and 69.8 % are respectively observed at 1 and 2 A cm−2, and 60 °C. Long durability of 2660 h is demonstrated at 1 A cm−2 and 60 °C. The post analyses of the CCMs suggest that collapse of the perovskite structure and dissolution of the constituent elements of SrTi0.67Ir0.33O3 are factors causing degradation.